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Speaking of Q measurements has anyone tried this EDN design: <https://www.edn.com/novel-q-meter/> Mike N2MS

On 3/22/21 7:58 PM, Roger Need via groups.io wrote: > I spent the afternoon building a spreadsheet to calculate the reflection coefficient and phase angle required for different values of reactance

On 3/22/21 8:52 AM, Manfred Mornhinweg wrote: >> Manfred's plots of the 2000pF 'Hi Q' capacitor (on the EFHW transformer >> thread) obviously had a problem somewhere with the test setup or maybe his

Here's a Q plot of an ancient Philips 470pF poly capacitor from about 1MHz to 20MHz. I measured it on a regular Agilent VNA and then on the little nanovna. Both VNAs use a basic SMA mechanical

I spent the afternoon building a spreadsheet to calculate the reflection coefficient and phase angle required for different values of reactance and capacitance. It was quite interesting to test

Another fairly crude form of verification would be to place a large resistor in parallel with the cap and see if the Q curve changes as expected. Also, it would be worthwhile extending the frequency

Hi, I can't find your jig. Could yo re-publish? Thank you, larry

The reflection coefficient phase angle should hardly change at all with the big change in Q of the 470pF cap from 300 to 3000 at 10MHz. It will change a tiny, tiny fraction of a degree. That's why I

Well, it does change! I just did the maths. But I have to concede that the phase change seems to be less important than the amplitude change. No, it also needs the amplitude! When the amplitude

Absolutely, you do have to be able to measure the angle of the reflection coefficient otherwise you wouldn't know it was a 470pF cap. But measuring this angle is very easy for the nanovna. The hard

I prefer to think in terms of amplitude and phase, R and X, rather than in reflection coefficient. Anyway, to measure the Q of a component it's necessary to measure both its reactance and resistance,

I do think it's more intuitive in this case to think in terms of the ability to measure the magnitude of the reflection coefficient rather than looking at resistance and reactance. For example, at

I think the nanoVNA measures the reflection coefficient of the network under test so I don't see how it can fail to measure the phase angle of the reflection coefficient with good results in this

Alan, Using a cavity would be roughly equivalent to my idea of using a crystal in series with the capacitor to be tested. With the crystal being suitable at HF and low VHF, and the cavity at high VHF

Everything is possible. But I do think that the main cause of the Q inaccuracy is the limits of the NanoVNA. It's just very hard to measure a very small resistance when it's in series with a very much

On 3/21/21 1:18 PM, jmr via groups.io wrote: > I think it's a bit optimistic to hope that a VNA could measure that component with a basic s11 measurement. I did a few quick sums and at 100kHz, a 485pF

I can't really see any difference on my device when leaving this set to auto or when setting it to 8mA as you describe. /Andreas - SA0ZAP

Well not quite, John. DiSlord has released v1.0.50 now.? :-) Mike - M0MLM ------------------------------------------------------------------------ *From:* John [mailto:k9ka@...] *Sent:* Monday,

Hi Group, I finally got my H4 VNA running with Dislord's V1.0.45. My solution was to first load Huygen's V1.0.45, which worked, and then follow up by loading the Dislord V1.0.45 which is now working

After reset calibration, select 8mA output (CALIBRATE->POWER->8mA) and after made calibration (this mode used in 0.8). This also reduce noise on measure. 1.0.50 version fix some bugs after 1.0.45